Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 d068951b45b9a783…

MALICIOUS

RTF / .DOC

19.5 KB First seen: 2021-09-17
MD5: d7674153a1e42d2d4b46a1c19ab7968d SHA-1: 9f01e4cfe5d60aa17042f000f276768619066b6b SHA-256: d068951b45b9a7837665384019e506bf0fdf37b6c160148e464228416aed42d6
180 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File T1059.003 Windows Command Shell

The RTF document contains embedded OLE object data, specifically related to Equation Editor. Heuristics indicate the activation of Equation Editor with a critical severity, strongly suggesting the exploitation of CVE-2017-11882. This vulnerability allows for arbitrary code execution when the embedded object is activated, likely leading to the download and execution of a secondary payload.

Heuristics 5

  • Obfuscated Equation Editor ProgID + activation critical CVE related RTF_EQUATION_EDITOR
    RTF decodes to an Equation.3 ProgID from top-level \objdata hex after nested RTF junk groups are ignored, and the document also contains \objemb plus \objupdate activation. This is an obfuscated Equation Editor exploit surface associated with CVE-2017-11882 / CVE-2018-0802 families, but no exact malformed MTEF CVE primitive was recovered from this object.
  • Equation Editor activation — CVE-2017-11882 related high CVE related CVE_2017_11882_ACTIVATION_RELATED
    RTF decodes to an Equation.3 ProgID and requests OLE activation with \objemb plus \objupdate. This reaches the legacy Equation Editor attack surface used by CVE-2017-11882/CVE-2018-0802 documents, but the malformed MTEF/native payload needed for stronger attribution was not recovered.
  • \objupdate forces OLE activation high RTF_OBJUPDATE
    RTF contains \objupdate — forces automatic OLE object instantiation when the document is opened, bypassing user interaction. Almost exclusively seen in Equation Editor exploit documents.
  • OLE object data medium RTF_OBJDATA
    RTF contains 2 \objdata section(s) — embedded OLE objects
  • Embedded OLE object medium RTF_OBJEMB
    RTF contains \objemb — embedded OLE object

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off0000053f.bin
fbb6a968a51b9af9738a9522b16c31e0c2b77581622cd3392fec12ca3e51a4ec		 rtf-objdata-decoded RTF \objdata at offset 0x53F 2019 bytes

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